In recent years in connection with the underseas exploration, drilling, and gathering of gas and oil, acoustic command and control apparatus, and acoustic communication systems have been widely used. One example of such equipment intended for use at deep sea depths is an acoustically actuated underwater release mechanism described in U.S. Pat. No. 3,848,226, issued Nov. 12, 1974, to G. R. Perez. In that underwater apparatus, an acoustic transducer is secured to a sealed tubular housing that contains electronic and electromechanical apparatus. The transducer is responsive to an acoustic command signal that is received from a transmitter associated with a surface vessel, for example. The transducer produces an electrical signal that is coupled to the electronic circuitry within the housing. The circuitry produces an actuating signal that causes an externally mounted latching mechanism to release.
Prior to deploying apparatus of the type described in the Perez patent, the electronic system in the apparatus is activated and tested. This may be aboard a work ship or barge prior to dropping the apparatus over the side. The housing of the apparatus is often subject to considerable vibration and other acoustic noise that is caused by the engine and other machinery on the work boat or barge. It has been found that these vibrations in the apparatus housing are mechanically coupled to the acoustic transducer and produce spurious and unwanted signals in the acoustic receiver system. These anomalous signals sometimes complicate the process of checking out the system. The problem is not present after the apparatus is in position in the water since the housing no longer is subject to the substantial shipboard vibrations.